Puyo Puyo 2 (WIN95) Sound Replacement (and possible other mods?)

[kielbasa]

Going back and playing the Windows port of Puyo Puyo 2 I noticed something funky. All of the in game sound effects seem to be 8000khz recordings of the C2/Megadrive original sound effects, but the new voices seem to be a much higher playback rate (more low quality sfx loaded in memory probably takes up less space than a small handful of voices for Arle + enemy for each round)

Seeing the magic that Matt had done with Lego Island has inspired me a bit.

Importing the WLK files in Audacity, I see that both the voice files (in the VI folder) and the game SFX (PUYO01, 02, etc in the root install directory) are all 11025khz audio files. I'm gonna make an educated guess that the WLK (and probably all the other files) are custom data containers made by Compile for this port that hold playback information somewhere in the file itself, as trying to tack on high quality sounds and just renaming a wav file outright crashes the game past the ACT AGAINST AIDS screen. Also seems that some of the voice line files have bits and pieces of other voice files split between them.

I'm an absolute nooblord when it comes to reverse engineering anything (the most effort I've put into a game mod is replacing sound effect WAV files in the PC port of Sonic 3D) but I'm also not against learning the necessary information to figure out how to achieve my end goal.

My question to the good people of this forum is, what would be a good starting point to deciphering the header information? I have tried opening the files in HxD but there doesn't seem to be anything relevant in the data readout.

Thanks for your time, I expect to get completely shit on for potentially missing something blatantly obvious somewhere lmao

[MattKC]

Since the audio data is uncompressed PCM, it probably shares a lot in common with the WAVE format, which is about as basic of an audio container as you can get. I'd recommend taking a look at the WAVE header specification, maybe opening a 11025KHz WAV file in HxD too, and seeing if you can recognize any similarities with the game files you're looking at. There should at least be bytes that specify the sample rate (11025) and number of channels (1 for mono, 2 for stereo, etc.); you can probably play around with them and see how it affects the sound in game. I was lucky in that LEGO Island's SI files actually just embed the main part of the WAVE header, so it was fairly trivial to reconstruct a file around that, however there's no guarantee this game will do that too. Still, as long as you know the sample rate, channel count, and format, you can create a WAV file (assuming your intention is to extract these sounds?)

If it's not WAVE, there's a chance it's AIFF, particularly if the game was primarily developed on/for Macintosh. That header is well-documented too, but I'm not familiar with it myself.

Good luck!